Exhibit 10.1


SECOND
AMENDMENT TO


SECOND
AMENDED AND RESTATED CREDIT AGREEMENT


THIS SECOND AMENDMENT TO
SECOND AMENDED AND RESTATED CREDIT AGREEMENT (this “Amendment”) is
entered into as of March 15, 2007, among MARKWEST HYDROCARBON, INC., a Delaware
corporation, as borrower (the “Borrower”), the undersigned Guarantors (collectively,
the “Guarantors”),
ROYAL BANK OF CANADA, as Administrative Agent and Collateral Agent for the
Lenders parties to the hereinafter defined Credit Agreement (in its capacity as
administrative agent, the “Administrative
Agent” and in its capacity as collateral agent, the “Collateral Agent”), and the
undersigned L/C Issuer and Lenders.


Reference is made to the
Second Amended and Restated Credit Agreement dated as of August 18, 2006 among
Borrower, the Administrative Agent, the Collateral Agent, the L/C Issuer and
the Lenders parties thereto, as amended by that certain First Amendment to
Second Amended and Restated Credit Agreement dated as of February 16, 2007 (as
amended, the “Credit Agreement”).  Unless otherwise defined in this Amendment,
capitalized terms used herein shall have the meanings set forth in the Credit
Agreement; all section and schedule references herein are to sections and
schedules in the Credit Agreement; and all paragraph references herein are to
paragraphs in this Amendment.


RECITALS


A.            The
Borrower has requested that the Credit Agreement be amended to make more
explicit that upon the effectiveness of the First Amendment, the Obligations
included all present and future indebtedness, liabilities and obligations owed
to any Lender or any Affiliate of a Lender arising pursuant to any Lender
Hedging Agreement and the Collateral secured all such indebtedness, liabilities
and obligations.


B.            Subject
to the terms and conditions of this Amendment, the Administrative Agent and the
other Lenders are willing to agree to such amendment.


Accordingly, for adequate
and sufficient consideration, the parties hereto agree, as follows:


Paragraph 1.        Amendments. Effective as of the Second Amendment
Effective Date, the Credit Agreement is amended as follows:


1.1          Definitions.
Section 1.01 of
the Credit Agreement is amended as follows:


(a)           Each of the following definitions is
amended in its entirety to read as follows:


“Collateral means all property and interests in property and proceeds thereof now
owned or hereafter acquired by the Borrower, and its Subsidiaries (other than
the Excluded MLP Entities) in or upon which a Lien now or hereafter exists in
favor of the Secured Parties, or the Administrative Agent or Collateral Agent
on behalf of the Secured Parties, whether under this Agreement, the Collateral
Documents, or under any other document executed by any Borrower Affiliate
(other than the Excluded MLP Entities) and delivered to the Administrative
Agent, Collateral Agent or the Secured Parties.”


“Collateral Documents means (a) each guaranty, pledge agreement,
security agreement, mortgage, assignment, and all other security agreements,
deeds of trust, mortgages, chattel mortgages, assignments, pledges, guaranties,
financing statements, 



                                                                                     
 









continuation statements,
extension agreements and other similar agreements or instruments executed by
the Borrower or any MarkWest Inc. Subsidiary for the benefit of the Secured
Parties now or hereafter delivered to the Secured Parties, the Administrative
Agent or the Collateral Agent pursuant to or in connection with the
transactions contemplated hereby, and all financing statements (or comparable
documents now or hereafter filed in accordance with the UCC or comparable Law)
against the Borrower or any MarkWest Inc. Subsidiary, as debtor, in favor of
the Secured Parties, the Administrative Agent or the Collateral Agent for the
benefit of the Secured Parties, as secured party, to secure or guarantee the
payment of any part of the Obligations or the performance of any other duties
and obligations of Borrower under the Loan Documents or the Lender Hedging
Agreements, whenever made or delivered, and (b) any amendments, supplements,
modifications, renewals, replacements, consolidations, substitutions,
restatements, and extensions of any of the foregoing.”


“Security Agreements means, collectively, the security agreements, or similar instruments,
now or hereafter executed by any of the Loan Parties in favor of the Administrative
Agent or Collateral Agent for the benefit of the Secured Parties, and all
supplements, assignments, amendments, and restatements thereto (or any
agreement in substitution therefor), and “Security Agreement” means each of such
Security Agreements and if hereafter executed such Security Agreement shall be
on substantially the same terms as the Security Agreements previously executed
by the Loan Parties.”


 (b)          The
definition of the term “Eligible Midstream
Accounts Receivable” is amended by deleting clause (xx) of such
definition and substituting therefor the following:


“(xx)        which is not subject to a first priority
and perfected security interest in favor of the Administrative Agent for the
benefit of the Secured Parties; or”


(c)           The following definition is inserted alphabetically into Section 1.01 of the Credit
Agreement:


“Secured Parties
means the Lenders party to this Agreement and the Lenders and/or any Affiliate
of a Lender party to a Lender Hedging Agreement.  The term “Secured
Parties” shall include a former Lender or an Affiliate of a
former Lender that is party to a Swap Contract with the Borrower or any of the
MarkWest Inc. Subsidiaries; provided that
such former Lender or Affiliate was a Lender or an Affiliate of a Lender at the
time it entered into such Swap Contract.”


(d)           Section
2.04(b)(vii) of the Credit Agreement is amended in its entirety to read as follows:


“(vii)       The Borrower hereby
grants to the Administrative Agent, for the benefit of the Secured Parties, a
lien on, and security interest in and to, the Proceeds Account and all monies,
cash, checks, drafts, certificates of deposit, instruments, investment
property, and other items received by Administrative Agent for deposit therein
and held therein, as security for the Obligations. The rights granted by this Section 2.04(b)(vii) shall be in
addition to the rights of the Administrative Agent under any statutory banker’s
Lien or the common law right of setoff.”


(e)           Section
2.11(d) of the Credit Agreement is amended in its entirety to read as follows:


“(d)         If at any time insufficient funds are received by and
available to the Administrative Agent to pay fully the Obligations, or if a
Default or Event of Default exists, any payment or prepayment shall be applied
in the following order: (i) to the 



                                                                                     
 









payment of enforcement
expenses incurred by the Administrative Agent, including Attorney Costs; (ii)
to the ratable payment of all other fees, expenses, and indemnities for which
the Administrative Agent or Lenders have not been paid or reimbursed in
accordance with the Loan Documents (as used in this Section 2.11(d)(ii),
a “ratable payment”
for any Lender or the Administrative Agent shall be, on any date of
determination, that proportion which the portion of the total fees, expenses,
and indemnities owed to such Lender or the Administrative Agent bears to the
total aggregate fees and indemnities owed to all Lenders and the Administrative
Agent on such date of determination); (iii) to the ratable payment of accrued
and unpaid interest on the Outstanding Amount of Loans and the Outstanding
Amount of Obligations under Lender Hedging Agreements (it being understood that
for purposes of this clause (iii) the Outstanding Amount of Obligations under
Lender Hedging Agreements refers only to payments owing pursuant to Section
2(a) of the 2002 Master Agreement  form
promulgated by the ISDA (or equivalent type payment obligation if some other
form of Swap Contract is in effect)(as used in this Section 2.11(d)(iii),
“ratable payment”
means, for any Lender (or Affiliate of a Lender, in the case of Lender Hedging
Agreements), on any date of determination, that proportion which the accrued
and unpaid interest on the Outstanding Amount of Loans and the Outstanding
Amount of Obligations under Lender Hedging Agreements owed to such Lender (or
Affiliate of a Lender, in the case of Lender Hedging Agreements) bears to the
total accrued and unpaid interest on the Outstanding Amount of Loans and the
Outstanding Amount of Obligations under Lender Hedging Agreements owed to all
Lenders (and Affiliates, in the case of Lender Hedging Agreements)); (iv) to
the ratable payment of the Outstanding Amount of Loans and the Outstanding
Amount of Obligations under Lender Hedging Agreements (it being understood that
for purposes of this clause (iv) the Outstanding Amount of Obligations under
Lender Hedging Agreements refers to payments owing in connection with an Early
Termination Payment as defined in the 2002 Master Agreement form promulgated by
the ISDA (or equivalent type payment obligation if some other form of Swap
Contract is in effect)(as used in this Section 2.11(d)(iv), “ratable payment”
means for any Lender (or Affiliate of a Lender, in the case of Lender Hedging
Agreements), on any date of determination, that proportion which the
Outstanding Amount of Loans and the Outstanding Amount of Obligations under
Lender Hedging Agreements owed to such Lender (or Affiliate of a Lender, in the
case of Lender Hedging Agreements) bears to the Outstanding Amount of Loans
owed to all Lenders)(and Affiliates, in the case of Lender Hedging
Agreements)); (v) to Cash Collateralize the Letters of Credit; and (vi) to the
payment of the remaining Obligations, if any, in the order and manner the
Required Lenders deem appropriate.”


(f)            Section
2.15(a) of the Credit Agreement is amended by deleting the first proviso at the
end of the first sentence of Section 2.15(a) and substituting the following
therefor:


“provided that any NBB Credit Extension
shall be used solely for the purpose of enabling the Borrower to meet margin
requirements under Swap Contracts with counterparties which are not Lenders or
Affiliates of Lenders;”


(g)           Section
2.17 of the Credit Agreement is deleted in its entirety and the following is
substituted therefor:


“2.17      Pari
Passu Lien Securing Lender Hedging Agreements.  All
Obligations arising under the Loan Documents, including, without limitation,
Obligations under this Agreement and Obligations under any Lender Hedging
Agreement (but not Indebtedness of the Borrower or any MarkWest Inc. Subsidiary
owing to any non-Lender or non-Lender Affiliate which enters into a Swap
Contract with the Borrower or any of



                                                                                     
 









the MarkWest Inc.
Subsidiaries), shall be secured  pari passu by the Collateral.  No Lender or any Affiliate of a Lender shall
have any voting rights under any Loan Document as a result of the existence of
obligations owed to it under any such Lender Hedging Agreement.”


(h)           Section
6.12 of the Credit Agreement is amended by deleting clause (C) at the end of
such Section and substituting the following therefor:


“(C) the NBB Revolving Credit Facility solely to enable the Borrower to
meet margin requirements under Swap Contracts with counterparties which are not
Lenders or Affiliates of Lenders.”


(i)            Section 6.16(a)
of the Credit Agreement is deleted in its entirety and the following is
substituted therefor:


“(a)         The Borrower shall and shall cause each of its Subsidiaries
(other than Excluded MLP Entities) to take such actions and to execute and
deliver such documents and instruments as the Administrative Agent shall
require to ensure that the Administrative Agent or Collateral Agent on behalf
of the Secured Parties shall, at all times, have received currently effective
duly executed Loan Documents granting Liens and security interests in
substantially all of the assets of the Borrower and each of its Subsidiaries
(other than Excluded MLP Entities), including all capital stock, partnership,
joint venture, membership interests, or other equity interests.”


(j)            The first sentence of Section 6.16(c) of the Credit Agreement is deleted in its
entirety and the following is substituted therefor:


“The
Liens required by this Section
6.16 shall be first priority perfected Liens in favor of the
Administrative Agent or Collateral Agent for the benefit of the Secured
Parties, subject to no other Liens except Permitted Liens of the type described
in Section 7.01
(other than Section
7.01(h)).”


(k)           Article IX of the Credit Agreement is amended by adding
thereto a new Section 9.12 to read in its entirety as follows:


“9.12      Hedging Arrangements.  To
the extent any Affiliate of a Lender is a party to a Swap Contract with the
Borrower or any of the MarkWest Inc. Subsidiaries and thereby becomes a
beneficiary of the Liens pursuant to the Security Agreements or any other
Collateral Document, such Affiliate of a Lender shall be deemed to appoint the
Collateral Agent its nominee and agent to act for and on behalf of such
Affiliate in connection with the Security Agreements and such Collateral
Documents and to be bound by the terms of this Article
IX, Section 10.01(e) and the last
sentence of Section 2.17.”


Paragraph 2.        Effective
Date. This
Amendment shall not become effective until the date (such date, the “Second Amendment Effective Date”)
the Administrative Agent receives all of the agreements, documents,
certificates, instruments, and other items described below:


(a)           this Amendment, executed by the Borrower, the Guarantors,
and each other Lender and the L/C Issuer;


(b)           from the Borrower and the existing Guarantors, such
certificates of secretary, assistant secretary, manager, or general partner, as
applicable, as the Administrative Agent may require, certifying (i) resolutions
of its board of directors, managers or members (or their equivalent)
authorizing the 



                                                                                     
 









execution
and performance of this Amendment and the other Loan Documents which such
Person is executing in connection herewith, (ii) the incumbency and signature
of the officer executing such documents, and (iii) no change in such Person’s
organizational documents since August 18, 2006;


(c)           fees and expenses required to be paid pursuant to Paragraph 5 of this
Amendment, to the extent invoiced prior to the Second Amendment Effective Date;
and


(d)           such other assurances, certificates, documents and
consents as the Administrative Agent may require.


Paragraph 3.        Acknowledgment
and Ratification. As a material inducement to the
Administrative Agent and the Lenders to execute and deliver this Amendment,
each of the Borrower and the Guarantors (i) consents to the agreements in this
Amendment, (ii) agrees and acknowledges that the execution, delivery, and
performance of this Amendment shall in no way release, diminish, impair,
reduce, or otherwise affect the respective obligations of the Borrower or any
Guarantor under the Loan Documents to which it is a party, which Loan Documents
shall remain in full force and effect, and all rights thereunder are hereby
ratified and confirmed.


Paragraph 4.        Representations. As a material inducement to the
Administrative Agent and the Lenders to execute and deliver this Amendment,
each of the Borrower and the Guarantors represents and warrants to the
Administrative Agent and the Lenders that as of the Second Amendment Effective
Date and as of the date of execution of this Amendment, (a) all representations
and warranties in the Loan Documents are true and correct in all material
respects as though made on the date hereof, except to the extent that any of
them speak to a different specific date, and (b) no Default or Event of Default
exists.


Paragraph 5.        Expenses,
Funding Losses.  The Borrower shall pay on demand all
reasonable costs, fees, and expenses paid or incurred by the Administrative
Agent incident to this Amendment, including, without limitation, Attorney Costs
in connection with the negotiation, preparation, delivery, and execution of
this Amendment and any related documents, filing and recording costs, and the
costs of title insurance endorsements.


Paragraph 6.        Miscellaneous. This Amendment is a “Loan Document”
referred to in the Credit Agreement.  The
provisions relating to Loan Documents in Article X of the Credit Agreement are
incorporated in this Amendment by reference. 
Unless stated otherwise (a) the singular number includes the plural and
vice versa and words of any gender include each other gender, in each case, as
appropriate, (b) headings and captions may not be construed in interpreting
provisions, (c) this Amendment must be construed, and its performance enforced,
under Texas law and applicable  federal
law, (d) if any part of this Amendment is for any reason found to be
unenforceable, all other portions of it nevertheless remain enforceable, and
(e) this Amendment may be executed in any number of counterparts with the same
effect as if all signatories had signed the same document, and all of those
counterparts must be construed together to constitute the same document.


Paragraph 7.        ENTIRE AGREEMENT. THIS AMENDMENT REPRESENTS
THE FINAL AGREEMENT BETWEEN THE PARTIES ABOUT THE SUBJECT MATTER OF THIS
AMENDMENT AND MAY NOT BE CONTRADICTED BY EVIDENCE OF PRIOR, CONTEMPORANEOUS, OR
SUBSEQUENT ORAL AGREEMENTS OF THE PARTIES. THERE ARE NO UNWRITTEN ORAL
AGREEMENTS BETWEEN THE PARTIES.


Paragraph 8.        Parties. This Amendment binds and inures to the
benefit of the Borrower, the Guarantors, the Administrative Agent, the L/C
Issuer, the other Lenders, and their respective successors and assigns.



                                                                                     
 









Paragraph 9.        Further
Assurances.
The parties hereto each agree to execute from time to time such further
documents as may be necessary to implement the terms of this Agreement.


The parties hereto have
executed this Amendment in multiple counterparts to be effective as of the
Second Amendment Effective Date.


Remainder of Page Intentionally
Blank


Signature Pages Follow.



                                                                                     
 









 


IN WITNESS WHEREOF, the
parties hereto have caused this Agreement to be duly executed as of the date
first above written.


	
  

  	
   

  	
   

  	
  MARKWEST HYDROCARBON, INC.,

  
	
   

  	
   

  	
   

  	
  a Delaware corporation, as Borrower

  
	
   

  	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
  By:

  	
  /s/ ANDREW L. SCHROEDER

  
	
   

  	
   

  	
   

  	
   

  	
  Andrew L. Schroeder

  
	
   

  	
   

  	
   

  	
   

  	
  Vice President, Treasurer and Assistant Secretary

  



 



                                                                                     
 









 


	
  

  	
   

  	
   

  	
  MARKWEST ENERGY GP,
  L.L.C.,

  
	
   

  	
   

  	
   

  	
  a Delaware corporation, as
  a Guarantor

  
	
   

  	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
  By:

  	
  /s/ ANDREW L. SCHROEDER

  
	
   

  	
   

  	
   

  	
   

  	
  Andrew L. Schroeder

  
	
   

  	
   

  	
   

  	
   

  	
  Vice President and
  Assistant Treasurer

  



 



                                                                                     
 









 


	
  

  	
   

  	
   

  	
  ROYAL
  BANK OF CANADA,

  
	
   

  	
   

  	
   

  	
  as Administrative Agent
  and Collateral Agent

  
	
   

  	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
  By:

  	
  /s/ GAIL WATKIN

  
	
   

  	
   

  	
   

  	
  Name:  

  	
  Gail Watkin

  
	
   

  	
   

  	
   

  	
  Title:

  	
  Manager, Agency

  
						



 



                                                                                     
 









 


	
  

  	
   

  	
   

  	
  ROYAL
  BANK OF CANADA, as
  a Lender

  
	
   

  	
   

  	
   

  	
  and L/C Issuer

  
	
   

  	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
  By:

  	
  /s/ JASON YORK

  
	
   

  	
   

  	
   

  	
   

  	
  Jason York

  
	
   

  	
   

  	
   

  	
   

  	
  Authorized Signatory

  



 



                                                                                     
 









 


	
  

  	
   

  	
   

  	
  SUNTRUST BANK,

  	 

	
   

  	
   

  	
   

  	
  as a Lender

  	 

	
   

  	
   

  	
   

  	
   

  	 

	
   

  	
   

  	
   

  	
  By:

  	
  /s/  CARMEN MALIZKA

  	 

	
   

  	
   

  	
   

  	
  Name:

  	
  Carmen Malizka

  
	
   

  	
   

  	
   

  	
  Title:

  	
  Vice President

  
							



 



                                                                                     
 









 


	
  

  	
   

  	
   

  	
  US BANK NATIONAL
  ASSOCIATION,

  
	
   

  	
   

  	
   

  	
  as a Lender

  
	
   

  	
   

  	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
  By

  	
  /s/  JUSTIN M. ALEXANDER

  
	
   

  	
   

  	
   

  	
  Name:

  	
  Justin M. Alexander

  	 

	
   

  	
   

  	
   

  	
  Title:

  	
  Vice President

  	 

							



 



                                                                                     
 









 


	
  

  	
   

  	
   

  	
  BANK OF OKLAHOMA, N.A.

  
	
   

  	
   

  	
   

  	
  as a Lender

  
	
   

  	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
  By:

  	
  /s/  MONICA M. MORTON

  
	
   

  	
   

  	
   

  	
  Name:

  	
  Monica M. Morton